Denison Barbs (aka Roseline Sharks) are a beautiful and active freshwater fish that make a great addition to just about any tank. We first experienced this species years ago, and have been big fans ever since!

Their care requirements are pretty straightforward, they look fantastic, and they’re also a lot of fun to watch. This is why we sing their praises to other aquarists all the time.

In this guide, you’ll learn everything you need to know about Denison Barb care. We cover tank mates, size, lifespan, diet, and plenty of other essential topics!

Species Summary

If you’re looking for a beautiful display of color in your home aquarium, the Denison Barb (scientific name: Sahyadria denisonii) is a freshwater species worth checking out.

A group of Denison Barbs swimming in a freshwater aquarium

Native to fast-moving rivers and streams in Western India, this fish is highly sought-after in the fish-keeping community. Their massive popularity paired with changes to their natural habitat is threatening wild populations.

Author Note: Luckily, local governments have banned exports of the fish. As a result, most of the specimens you see in the trade are commercially bred.

The Denison Barb goes by many names. You might see it labeled as the Roseline Shark (even though they’re not technically a freshwater shark), Red-Line Torpedo Barb, or even the Miss Kerala.

But whatever it’s called, there’s no mistaking its beautiful looks!

These fish make great additions to large tanks. Their bright coloration and active lifestyle will provide years of enjoyment for any aquarist.

Lifespan

With a proper diet and a well-kept habitat, Denison Barbs have a lifespan of up to five years in captivity.

While there’s always a degree of chance and good luck with captive fish, how you care for them will impact their life expectancy significantly. If you don’t provide pristine care, your Roseline Shark could suffer from disease and a severely shortened lifespan.

Appearance

The Denison Barb is one of the more colorful species in the aquarium trade. Their bodies are covered with several colors and some intricate details

The body of the Dension barb is long and torpedo-shaped. It has a base color of silver. You may see some tinges of yellow or gold as well depending on the lighting conditions.

One Roseline Shark looking for food in the tank

Running along the length of the fish is a black lateral stripe. It runs from the tip of the snout down to the base of the caudal fin. Above that, is a parallel stripe of red! The scarlet line starts at the snout, runs through the eye, and fades away at the fish’s midsection.

You may also see a vibrant band of red on the front of the dorsal fin. The tailfin, however, has stripes of dark black and yellow. The striping detail can be found on the tips of both forked ends.

Finally, there’s the head. Mature specimens will often develop a beautiful shade of emerald green on the head.

Author Note: There aren’t too many differences between male and female Roseline Shark. The easiest way to distinguish between the two is by looking at size. Females get slightly larger than males. Females may also have duller coloration.

Average Size

The average Denison Barb size is around six inches in length when fully-grown. Thanks to their large size, their color details are very visible (making them a great fish to spectate).

However, it also means that you will need a sizable tank to keep them comfortable. These fish have a fairly steady growth rate so they’ll grow up before you know it!

Denison Barb Care

Denison Barb care isn’t a very difficult process if you’re comfortable with the fundamentals. However, their active lifestyles and sensitivity to water changes will require a bit of attention and preparation.

To keep your Roseline Shark healthy, here are some care guidelines you need to follow:

Tank Size

The biggest obstacle you might face when preparing your fish’s new home is providing enough space. These fish can get fairly large as adults. Not only that, but they are powerful swimmers! Thus, you need as much space as possible.

The minimum tank size requirement for Denison Barbs is 55 gallons. That should suffice for a small group of these fish. However, if you want to create a large multi-species community tank, you’re going to need something far bigger.

Author Note: A larger tank is always recommended if you have enough room in your home. That is especially true with active swimmers like the Denison Barb.

Water Parameters

Denison Barbs come from highly oxygenated bodies of water that are teeming with plant life. You must replicate this environment to help your fish reach their full potential.

The good news is that Denison Barbs can tolerate a generous range of parameters. As long as you stick within the acceptable ranges and avoid any major fluctuations, you should not have any major problems.

  • Water temperature: 60°F to 77°F (aim for the middle of this range)
  • pH levels: 6.6 to 7.8
  • Water hardness: 5 to 25 dGH

We highly recommend getting a trustworthy and accurate water test kit to monitor these parameters throughout the week. If you’re not getting the right information from your test kit it can cause you to make unnecessary changes to the water.

Perform tests more regularly when you first get your Roseline Sharks. As they get used to their new home, you can decrease the frequency of tests a bit.

Setting Up The Inside Of Their Tank

Planning the decor is just as important as keeping the water parameters just right.

Denison Barbs need natural decor that’s reminiscent of their natural habitat. Without it, the fish can become stressed and lose its coloration.

Starting at the bottom of the tank, apply a layer of sand or fine gravel. You can add some rocks and pebbles to the substrate for a more natural look.

Then, add some plants. You can choose plants like Anubias, Java Fern, and anything else that adds some vegetation to the environment. Just make sure that everything is anchored in nicely.

Author Note: You will need to pay close attention to how secure these plants are. Denison Barbs are notorious for uprooting plants as they zip through the tank.

For some solace away from the commotion, create some hiding spots. You can do this with driftwood, rocks, and other natural decorative items. These hiding spots will provide them with a safe place to go if they want some privacy.

But the most important thing these fish need is an open swimming space.

This means you should take care to not overcrowd the tank with decorations. Give your fish some room to dart around!

A few Sahyadria denisonii in a well-planted tank

Roseline Sharks need strong flow and good oxygen levels, too. To accomplish that, use a powerful filtration system with a robust outlet tube. Alternatively, you can use submersible jets to create this effect as well.

Position them so that they point down the length of the tank. This will keep the water oxygenated while providing adequate flow.

Lastly, top your tank off with a secure lid. Denison Barbs are known to leap out the water from time to time.

Potential Diseases

Denison Barbs don’t suffer from a species-specific disease. However, they can experience all of the common ailments that affect freshwater fish.

In fact, Denison Barbs may be more sensitive to issues like Ich than many other species. Ich is a disease that covers the fish in tiny white spots. It’s typically a byproduct of stress, which is caused by poor living conditions.

Denison Barbs are used to living in pristine conditions. Their natural habitats in the mountains of India are clean and clear. They will not tolerate waste buildup in the tank.

If you let waste accumulate, you will have to deal with stress-related diseases like Ich. Make sure that you’re using a powerful filtration system and performing regular water changes.

Vacuum up waste and leftover food. You should also clean the gravel regularly. Taking all of these steps will keep ammonia and nitrate levels undetectable, which will help your fish avoid disease.

Food & Diet

Natural omnivores, Denison Barbs will eat anything you provide. In the wild, they typically feed on algae, small invertebrae, and insects.

Providing a balanced diet is crucial! Not only will it keep your fish healthy, but it’ll make all the beautiful coloration more vivid than ever!

For simplicity, you can provide standard flakes or pellets as the base of their diet. For optimal color, choose a balanced product with carotenoids.

You can supplement the dry food with live and frozen foods. The fish enjoy brine shrimp, daphnia, bloodworms, and spirulina. Blanched vegetables work great, too.

Author Note: Feed your Denison Barbs twice a day. Only provide enough food that they can consume in about two minutes to preserve water quality and avoid overfeeding.

Behavior & Temperament

Denison Barbs are considered to be a peaceful fish. They can get along with other non-aggressive tank mates that like to stay active.

However, their good behavior is dependent on the amount of space they have. When kept in tight quarters, the fish can compete with others and may show some aggressive tendencies.

Even in large tanks, Denison Barbs may accidentally cause some trouble. They are fast swimmers, so you should never put them with slow-swimming fish. Otherwise, accidents and injuries are bound to happen.

Throughout the day, you can observe these fish darting around the tank. They like to group up and swim in unison, creating a beautiful display of color.

This is one of the reasons we recommend them so often. Roseline Sharks are an incredibly entertaining freshwater fish to observe!

Denison Barb Tank Mates

It’s best to keep a small group of Denison Barbs together. These fish do not do well when they’re alone and rely on social interaction to stay healthy.

At the very least, you should keep a group of half a dozen.

Beyond other Denison Barbs, you have a few options when it comes to compatibility. In general, try to stick to similar-sized fish that can swim fast. Slow fish with delicate fins are not recommended!

Here are some good tank mates for the Denison Barb:

Breeding

While Denison Barb breeding happens all the time in commercial operations, it’s very rare to see success in a standard home aquarium. It can occur by chance, but triggering the spawning process is nearly impossible.

Commercial breeders utilize hormones and elaborate setups to get the job done. Currently, there are no known methods to get the fish to breed naturally.

Because of this, we don’t recommend attempting to do this at home. While it might seem like something fun to try, the chance of success is pretty much nonexistent.

Attempted breeding can cause unnecessary stress on your fish, without the reward of spawning. If someone comes up with a way to breed Roseline Sharks at home in the future we’ll definitely update this section of the guide!

Conclusion

Denison Barb care is something we think every aquarist can handle, as long as they’re committed to maintaining great water quality. These fish are actually pretty low-maintenance if you stay on top of things!

We hope this guide taught you a lot about this species and made you better-prepared for owning one in the future. We can’t recommend them enough.

If you have any other questions about the Roseline Shark that we didn’t cover in this guide, send them over! We’ll do our best to answer them as fast as we can.

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